Medical devices such as implantable pulse generators typically include a primary circuit board that contains various electronic devices such as microcontrollers, waveform generators, and the like. These electronic devices may be used to create stimulation signals that provide therapy to a patient in some cases, this circuit board may be of a flexible nature while in other cases this circuit board may be rigid or semi-rigid.
Various other electronic components of the medical device may be located separately from the circuit board. For instance, a battery may be present and have a connection point where the electrical contacts of the battery are present. Likewise, a stimulation capacitor may be present and have a connection point where the electrical contacts of the capacitor are present. A feedthrough interconnect may be present to provide a conductive pathway for stimulation signals to be passed outside of the sealed housing of the device and the feedthrough may have a connection point where electrical contacts are present.
The primary circuit board relies on the interconnections to these various other electronic components. Conventionally, one or more flexible circuit bodies are used to provide this interconnection. However, these flexible circuit bodies include relatively large ribbon conductors that have been bonded or otherwise attached to the flexible circuit bodies to establish electrical connections to circuit traces within the flexible circuit bodies. These relatively large ribbon conductors on one end of the flexible circuit body may then be bonded or otherwise attached to relatively large electrical contacts on the primary circuit board while relatively large ribbon conductors on the opposite end of the flexible circuit body may then be bonded or otherwise attached to relatively large electrical contacts of the other components.
This conventional approach to interconnecting the primary circuit board to the various other electrical components has several drawbacks. For instance, the addition of the ribbon conductors to the flexible circuit body requires steps necessary to add these additional parts. This process introduces costs, time, and potential faults into the construction of the flexible circuit body.
Furthermore, these ribbon conductors are relatively large, often on the order of 5 to 10 thousandths of an inch thick. The bond pads that receive these ribbon conductors are in proportion to the ribbon conductors and therefore are relatively large as well. The relatively large size of these ribbons thereby constrains efforts to miniaturize the medical device.